焼結高速度鋼の諸性質に及ぼす炭化物量および炭素量の影響
1998 年 84 巻 4 号 p. 315-320
詳細
1998 年 84 巻 4 号 p. 315-320
In order to improve the performance of sintered high-speed-steels by increasing carbide fractions and carbon contents and to clarify the limits of their addition, several properties of high-speed-steels having higher carbide fraction and carbon content than conventional ones have been investigated. Carbide fractions were controlled by changing the W, Mo and V contents of atomized powder. Specimens were prepared by vacuum sintering of cold-compacted water atomized powder consisting of fine solidification structure.
The upper limit of carbide fraction was found to be about 43 area%, because the bending strength decreased with the formation of network carbide structure. The upper limit of carbon balance (Cbal), converted into carbon content, was about 0.15, because above 0.15, the tempered hardness decreased with the increase in retained austenite, and, the bending strength decreased with coarsening of carbides after sintering. The chemical compositions of 2.8C-13W-11Mo-8V-8Co and 3.2C-12W-8Mo-10V-9Co showed superior performance to conventional high-speed-steels.
